The present invention relates to method for manufacturing a multicolor filter by electrodeposition and a method for manufacturing a multicolor display device utilizing the multicolor filter.
Conventionally a monocolor filter which is colored by diffusing metal atoms into a glass substrate has been widely used for cameras. Recently a multicolor filter having fine patterns has been required for image camera tubes. The multicolor filter is made by printing the multicolor pattern on a glass substrate or by photolithography in which a colored layer is formed on a glass substrate and then the colored layer is exposed to ultra violet light through a mask to be etched in the desired pattern by the photolithographic method. Such a process is repeated for different colors so that a fine multicolor filter is obtained. Quite recently a multicolor display device comprised of a liquid crystal display device and the multicolor filter having a fine pattern has been developed. Hereinafter such a prior art multicolor display device is briefly explained.
FIG. 1 shows an embodiment of a prior art multicolor display device using a color filter. In FIG. 1, numeral 1 denotes a transparent substrate, 2 denotes a display electrode consisting of a transparent electroconductive film on which a figure or a letter is patterned, 3 denotes a color filter tightly formed on the surface of the display electrode 2, 4 denotes a transparent counter electrode, and 5 denotes a transparent counter substrate. A material serving as an optical shutter and comprised of liquid crystal or electrochromic material which has the property of being opened or closed by an applied voltage is filled between a space sandwiched by the two substrates 1 and 5. The color filters 3, 3' and 3" are in different color tones. When a voltage is selectively applied between the display electrodes 2, 2' and 2" and the counter electrode 4, a multicolor display is made.
A multicolor display using a color filter is highly effective for practical use because the method is simple, a free choice of color tones can be easily obtained, and it can be combined with various display materials and systems.
As understood above, the requirement for the multicolor filter having a fine pattern increases while the fabrication process has to be easy and to be accurate in fineness of the multicolor pattern. However the conventional printing method does not achieve enough fineness though it is a easy method to carry out. The other conventional photolithography method requires precise alignment of the mask during the exposure of the ultra violet light and is very complicated to carry out though it achieves high accuracy of the pattern.